Tetrahedral DNA nanostructures (TDNs) is the self-assembly product based on DNA nanotechnology. Due to its advantages of simple synthesis method, high yield, stable structure, excellent mechanical properties and rich molecular modification sites, it is widely studied and applied in molecular diagnosis, bioimaging, molecular delivery and targeted drug delivery, etc. Compared to most of the traditional nano materials, TDNs can be transported to cell lysosomes through caveolin-mediated endocytosis pathway and microtubule-dependent pathway and can maintain the structure in cells for a long time. It has been reported that the TDNs can successfully transport the immunostimulant CpG into cells to take effect. However, as with the individual TDNs, the drugs are also carried into the lysosomes, which lead to the rapid degradation of drugs by lysosomes.
Nucleic acid aptamer AS1411 is a single-strand DNA that can specifically bind to pyrenin. Pyrenin is highly expressed on nucleus and the surface of the tumor cell membrane. Moreover, the AS1411 can be mediated into nucleus by pyrenin to inhibit the DNA replication, so as to force the cells to stay in S phase, thereby inhibiting cell proliferation. Meanwhile, AS1411 interferes the binding of pyrenin and bcl-2 so as to promote apoptosis of cells. Hence, AS1411 has a great prospect in cancer diagnosis and treatment.
However, the TDNs and AS1411 in combination with nucleic acid drugs for preparing a drug delivery system has not been reported yet.